Golf club “metal woods”, were originally manufactured primarily by casting of durable metals such as stainless steel, aluminum, beryllium copper, etc. into a unitary structure comprising of a metal body, face and hosel. As technology progressed it became more desirable to strengthen the face of the club, and usually this was achieved by using titanium material.
With a high percentage of amateur golfers constantly searching for more distance on their drives, the golf industry has responded by providing golf clubs specifically designed with distance in mind. The head sizes have increased which allows for the club to possess a higher moment of inertia, which translates to a greater ability to resist twisting on off-center hits. However, as a wood head becomes larger, its center of gravity will be moved back away from the face resulting in hits flying higher than expected. Reducing the lofts of larger head clubs is one way to compensate for this. Also with the larger heads, the center of gravity is moved further away from the axis that is created by the intersection of the hosel with the sole plate. This can cause these large head clubs to remain open on contact, thereby inducing a “slice” effect (in the case of a right-handed golfer, the ball deviates to the right). Offsetting the head and incorporating a hook face angle can help compensate for this by “squaring” the face at impact, but often more is required to eliminate the “slice” tendency.
The technological breakthrough in recent years towards providing the average golfer with more distance, by increasing the club head size, has been to keep the weight constant or even lighter, by casting consistently thinner shell thickness and going to lighter materials such as titanium. Also, the club head faces have been steadily becoming extremely thin. These thinner faces will maximize what is known as the Coefficient of Restitution (COR), which means that the more the face rebounds upon impact, the more energy that may be imparted to the ball, thereby increasing distance. In order to make the faces thinner, manufacturers have moved to forged or stamped metal faces which are stronger, in most cases, than those that are cast. Common practice is to integrate the forged or stamped metal face by welding it to the body at the sole and crown transitions. These transitions are the points on the club head that absorb the greatest amount of stresses as the club strikes the ball.
A common feature of most metal wood designs that exhibit a thru-hosel construction is that there is an intimate connection between the face, hosel tube and heel portion of the skirt wall. This often results in a reduced unsupported face area due to a narrower supporting perimeter, thereby reducing the overall face flexibility and “sweet spot”.
Therefore, it is very desirable to provide a method for attaching the impact face portion to the body of the club head without sacrificing any COR (Coefficient of Restitution) value or “sweet spot” size.